In the process of image generation and transmission, the image quality is often degraded due
to the interference and influence of various noises, which will have a negative impact on the
subsequent image processing and image visual effect.
Therefore, in order to suppress noise and improve image quality, denoising methods need to be applied.
The main methods to remove noise are spatial filter, transform-domain filter and so on.
Spatial filtering directly performs data operation on the original image and processes the grey
value of the pixel, such as the Median filter and low-pass filter [1]}.
The transform-domain filter contains Fourier transform and wavelet transform [2]}.
